Symmetries of Four-dimensional String Effective Action with Cosmological Constant
Abstract
Description
Classical solutions for a four-dimensional Minkowskian string effective action and an Euclidean one with cosmological constant term are derived. The former corresponds to electrovac solutions whereas the later solutions are identified as gravitational instanton solutions for Fubini-Study metric. The symmetries of the effective actions are identified and new classical solutions are generated by implementing appropriate noncompact transformations. The S-duality transformations on the equations of motion are discussed and it is found that they are S-duality noninvariant due to the presence of cosmological constant term.
13 pages, RevTex file, text is improved, no changes in the final results, also some references are added. (version to appear in Phys. Lett. B)
13 pages, RevTex file, text is improved, no changes in the final results, also some references are added. (version to appear in Phys. Lett. B)